光催化剂NH2-MIL-125(Ti)的制备及其催化去除NOx性能影响研究

光催化作为一种绿色、可持续、低耗费的催化技术,在有效净化大气中低浓度NOx(ppb级),保证空气质量、区域和全球气候方面具有极大的应用潜力。针对现有的无机半导体光催化剂存在的吸附容量小、对低浓度的NOx的吸附速率低和光生电子-空穴易复合导致光催化效率低等问题,本研究提出合成具有超高比表面积及孔隙率的有机金属框架作为光催化剂去除大气中低浓度NOx,通过改变催化剂制备时间,采用溶剂热法合成不同反应时间的NH2-MIL-125(Ti)晶体,探究制备时间对催化剂的光催化性能影响。采用XRD、SEM、FTIR、PL、EPR和BET等实验表征手段对不同NH2-MIL-125(Ti)晶体结构、形貌表征及光催化性能分析,并进一步探究其对NOx催化性能与催化制备时间的关系。研究结果表明,制备时间对NH2-MIL-125(Ti)的结晶度、表观形貌、光生电子-空穴复合效率、表面超氧自由基产生量都有一定的影响,对表面官能团种类、光吸收范围、晶格晶面没有影响。 制备时间为24小时、48小时、72小时NH2-MIL-125(Ti)对NOx的净化效率分别为38.22%、42.24%、32.04%,得出结论：当制备时间为48小时NH2-MIL-125(Ti)对NOx的催化性能最好,净化效率最优。

Research on the Preparation of Photocatalyst NH2-MIL-125(Ti) and Its Performance of Photocatalytic Removal of NOx

As a green, sustainable, and low-cost catalytic technology, photocatalysis has great application potential in effectively purifying the atmosphere at low concentrations of NOx (ppb level), ensuring air quality, regional and global climate. The inorganic semiconductor-based photocatalysts have several disadvantages, such as small adsorption capacity, low adsorption rate for low concentration NOx, and easy recombination of photogenerated electrons and holes, resulting in low photocatalytic efficiency. Therefore,this study proposed to synthesize metal-organic frameworks(MOF) material with ultra-high specific surface area and porosity as photocatalysts to remove low-concentration NOx in the atmosphere. NH2-MIL-125(Ti) crystals were synthesized by the solvothermal method with different reaction time, and the effect of preparation time on the photocatalytic performance of the catayst was explored. XRD, SEM, FTIR, PL, EPR, and BET were used to analyze the structure,morphology and photocatalytic performance of different NH2-MIL-125(Ti)crystals. The relationship between the NOx catalytic performance and the catalytic preparation time was further explored. The results showed that the preparation time has a certain influence on the crystallinity, apparent morphology, photogenerated electron-hole recombination efficiency, and surface superoxide radical production of NH2-MIL-125(Ti). But it has no effect on the surface functional group type, light absorption range, and lattice crystal plane. The purification efficiencies of NH2-MIL-125(Ti) on NOx were 38. 22%,42.24% and 32. 04%,respectiuely, corresponding to the preparation time of 24 hours,48 hours,and 72 hours. As a result, NH2-MIL-125(Ti) prepared under 48 hours showed optimal catalytic performance and purification efficiency.